Secret telegraphic system



A. J. EAVES.

SECRET TELEGRAPHIC SYSTEM.

APPLICATION FILED JUNE 24,1918- Patented Oct. 26,1920.

/n venfa Auguc/am Jfave a UNITED STATES[PAr-ENrPoFi-icE.

AUGUSTUS .r. EAVES, or NEW YORK, n". Y., AssIcuoR To wEs ii ELECTRIC comrm, mconrom'rnn, or NEW voax, N. Y., A coaro m'rron or m YORK.

SECBET TELEGBAPHIC SYSTEM.

- Specification of Letters Patent. Pate t d 0a, 2 0

Application filed June 24, 1918. Serial No. 241,608. r

i T 0 all whom may concern Be it lmown that I, AUcUs'ros J. EAvns, a citizen of the United States, residing at New York, in the county of New York,

State of New York, have invented certain new and useful Improvements in Secret Telegraphic Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telegraph systems, and more particularly to systems for rendering secret telegraphic service.

The principal object cf the invention is the provision of a telegraph s stem wherein means is provided for preventing the intelligent interception of a message while it is being communicated between two distant stations.

In accordance with theinvention means is provided which is responsive to the actuation of a transmitting mechanism for causing the operation of additional means whereby the character impulses constituting a message are divided between a plurality of conductors extending between two distant stations. 1

To the end that the foregoing objects may be attained the present invention contemplates the employment of electroresponsive devices respectively under the control of telegraphic transmitting and receiving equipments located at remote points on a line circuit, the arrangement to be such that message currents of one or more telegraphic channels may be switched or interspersed between a plurality of line conductors extending between such remote points. Although the telegraphic messages of the various channels would be unintelligible to persons who may tap either or all of the line conductors, the automatic functioning of the devices of this invention will, nevertheless, re-

sult in each message being properly repro duced through. the control of an associated receiving equipment. Since the present system provides a system to battle the efforts of any one'who may seek to intercept a message under transmission it may be properly referred to as a secret telegraphic system.

This invention is illustrated diagram matically in the accompanying drawing, and for the sake of clearness,'0nly so much of a telegraphic equipment has been shown as will be necessary to a ready and clear underment shown in Fig. 1 principally with re spect to details in the organization of the apparatus. I

In describing the operation of this system attention will first be directed to Fig. 1 of the drawing, wherein the reference charac-- ter A indicates telegraphic equipment at one station which is connected by means of two line conductors I1 and L with a similar equipment 13 at a second station. At the first station A a telegraphic group C comprising a transmitting key 4, a line relay 5 and an electromagnet 6 which may be-in the form of arreading sounder or a relay device suitable for the reception of signaling currents, is associated for-communicating with a similar group D comprising a key 44, a line relay 45 and a sounder 46 at the second station B. Similar telegraphic communications may be carried on by means of a key 7, a line relay 8 and a sounder 9, indicated as a group E at the first station, with a group F comprising a key 47, a line relay 48 and a sounder 49 at the second station. At the station A three polar relays 10, '16 and 19 are connected to be controlled by momentary currents which may be set up, as will presently appear, in a secondary winding 15 of a current transformer 13. The relay 10 serves as a pole changer in controlling the connecting of oppositely poled batteries 11 and 12 with a local circuit formed serially through a primary winding 14 of the transformer 13, the winding of the sounder 6 and the contacts of the line relay 5. The relays 16 and 19 are arranged to reciprocally control the switching of the sets C and E from one to the other of the. line conductors L and L In Fig. 2

' trolled b momentary currents in. a second- At the second station B a somewhat simirelays 50, 56 and 59, connected to be con-.

ary win ing of a transformer 53. The relay 50 is connected to act as a pole changer in connecting oppositely poled line batteries 51 and 52 through a circuit formed by the primary Winding' 54 of the transformer 53, the key 44, the l1ne relay 45, and, during the time the equlpment 1s in the position in which it is shown in the drawing, over the contacts 57 of the relay 5 6, the line conductor L thence over the contacts 17 of the relay 16 at the station A, the windingI of the line relay 5 and the key 4 to earth. n a manner corresponding with the service of the relays 16 and 19 at the first station the relays 56 and 59 at the second station serve to reciprocally switch the telegraphic sets D and F from one to the other'of the line co nd1 1cors L and L As shown in the drawing, dur1n the time the sets C and D may be joine over theJline L the sets E and F will be joined by way of the contacts'2O and 60 of the relays 19 and 59, respectively, over the line conductor L In a reciprocal manner, during .the time the polar relays 16 and 19, 56 and 59 may be standing in positions opposite to those shown the'sets C and D will be joined by way of the contacts 18 and 58 of the relays 16 and 56, respectively,

and the line conductor L while the sets E and F will be connected over the contacts 21 and 61 respectively of the relz%s 19 and 59 by way of the line conductor The polarized relays at each station are non-biased; therefore their armatures will remain in either position to which they may be moved by a momentary impulse of operating current. It may also be pointed out that the time constant of operation of the relays5, 45, 8 and 48 is ordinarily lower than the time constant of operation of the polar relays; therefore in the operation of the system a line relay may be initially operated by current routed over one line conductor, following which, the polar relays may so quickly switch the line connections that the line relays'will not have sufiicient time in which to release and may therefore continue operated-by current routed over the other line conductor.

In more specifically considering the oper ation of this system a few transmitting operations will be assumed and traced through their various successive steps. As a first example, let it be assumed that .while the equipment is at rest irrthe position in which 1t is shown, at the set D the transmitting key 44 is opened, preparatory, to sending a message. This operation first interrupts the line circuit as already traced from the battery 51, and this cessation of current formers,

through the winding 54 0f the transformer 5.3 induces a momentary current in the secondary winding 55 of this transformer. At'

the station A this interruption of the line current permits the line relay 5 of the set C to release and disconnect the local circuit whereby cessation of current from the battery 11 through the primary winding 14 of the transformer 13 induces a momentar current in the secondary winding 15 of thlS transformer. The effect of the induced impulse in the transformer at each station operates the associate polar relays, causing their armatures to assume the bias or position opposite to that in which they are shown. Atvthe station A the relays 16 and 19 thereby connect the set C ductor L and the set E to the line conductor L while the relays 56-and 59 at the station B connect the set D to the line conductor L and the setF to the line conductor L At each station the third polar relays 10 and 50 respectively disconnect the batteries 11 and 51 and prepare circuits from the batteries 12 and 52. Therefore, assuming that the key 44 is now moved to its closed position current from the battery 52 will complete circuit over the path already traced through the line relay 5 at the first station.

-This l1ne current in flowing through the transformer .winding 54 at the station B and in operating the line relay 5 to close the local circuit through the transformer wind ing 14 at the station A, although causing a momentary current to be set up in the respective secondary windings 15 and 55 of these transformers has no effect with respect to the polarized switching relays, since the-opposite polarity of the batteries 12 and 52 with respect to the batteries 11 and 51 results in the induced currents having a polarity or direction corresponding with the direction of the induced currents whichresulted from the interruption of current through the primary windings of the transas already described. Accordingly the associated polar relays at each station will be unaffected by the transformer currents corresponding with actions taking place through the closure'of the key 44, but' will continue in the position to which they mayhave been biased due to the circuit effects which resulted from the opening of this key.v If now the key 44 is again opened, cessation of the positively poled current from the battery 52 in the transformer to the line conwinding. 54 and corresponding cessation of current from the positively poled battery 12 in the transformer windin 14 will respectively induce currents in t e secondary windings 15 and 55 of such direction that the associated polar relays at each station will be operated and bias their armatures to the positions in which they are shown in the drawing. The line conductors will accordinglybe transposed with respect to the sets C and D, and E and F, while the batteries 12 and 52 will be; disconnected and circuits respectively prepared from the batteries 11 and'51.

From the foregoing description it will be clear that during the time messages may be under transmission from the set D to the set ,C the key 4=4.also serves as a master in controlling the switching of the line and local circuits at each station, in order that the secret service features of this system, may be carried out. It will also be obvious that during the time messages may be under transmission from the set D at the second station to the set C at thefirst station or in a reverse direction between these sets, messages may be transmitted either from the set E to the set F or from the set F to the set E. This is possible since the switching relays at each station operate in a relatively simultaneous relation, thereby insuring that during the time the associated sets C and D may be connected over the line conductor L the associated sets E and F will be connected over the line conductor L and vice versa.

In transmitting from the set C to the set D the key 4 serves as a master in initiating operations whereby the polar relays at each station will respond in providing the secret service eflects. Since the key 4: at the station A effects operations identical to the operations of the key 44, at the station B, in

opening and closing the same line circuit, it will be clear from the descriptions already given that the master control by the key 4 is typical of the master control by the key 44, and therefore, further description of these operations will not be necessary.

With regard to the connective relation of the transformers and their respectively associated polar relays it will be mentioned that instead of this relation being in accordance with the arrangement assumed for pur pose of illustration, in the foregoing descriptions the connections may be so arranged that the pol ar relays will respond to current induced at the instant the polechanger relays 10 and 50 respectively complete circuit to either one of their associated batteries. Under this arrangement the po-' lar relays would move their armatures following each closure of either the key 4 or the key 54, no response of these relays taking place at the instant either of the keys may.

be opened. Therefore in transmitting messages in either direction between the master sets C and 'D the first portion of each impulse would be transmitted over one line conductor, while the remainder of the same impulse would be transmitted over the other line conductor. Such relation of the operating circuits is possible through the difference in the time constant relation between the polarized relays and the linerelays, as

already referred to. For the last assumed, relation of the polar relays and their respective transformers a design or an adjustment whereby the line relays may operate quickly under energization nd release slowly under deener ization constitutes a desirable feature o the present system, and conversely,

for the first assumed relation in which the polar relays respond at moments the key of either master set is opened a design or adjustment of the relays whereby they may In operating the system according to the relation wherein the switching relays respond at moments the transmitting key on by individual impulses may be transmitted between the sets'C and D are deleted with respect to either line conductor; second, similar deletionmay also take place with respect to currents forming individual impulses which may be under transmission between the sets E and F; and third, complete impulses forming irregular fragments of messages under transmission between the latter sets may be interspersed between such currents of the first sets as form portions of individual impulses. Therefore, it will be readily apparent that in case the line conductors may be tapped it would be possible to receive onlyan incoherent and hetero geneous jumble ofimpulses, impossible of translation. As a further safeguard, however, the line conductors may be remotely routed, one conductor from the other, or one conductor may be routed through a cable while the other conductor may be carried in the form of an open wire line along the same right of way. By this arrangement it wduld not be possible for both of the line either master set may be closed the service results may be briefly summarized as follows: First, portions of the curents whereas the master set whereby the polar relays of a tery time, and the transmitting set H alone serves lishlng the ne ati-ve battery 64 t6 cause the distant line relay 5 to close its local circuit and to connect the battery 52 through the stransformer winding 54. At the relay 5 the local circuit including the transformer winding 14 now stands completed from the bat- 12. I Since the polarity relation of the the secret service may be controlled. In debatteries with the respective transformers is scribing these control operations the key 44 in opposite direction with respect to the curcontrols a pole-changer relay 62 and a secret rent present at the instant the circuits were control rela 63. The relay 62 controls the interrupted the impulse induced in the secinclusion o oppositely poled line batteries ondary windings W11]. be in the same direction 64 and 65 with the polar relay 45 which is as the last impulse and therefore the respecarranged with an artificial line AL to form! tively associated switching relays will not be relays 62 and 63, thereby respectively estab- I a diilerential duplex equipment. Such outaflected but continue in the positions to going currents, although neutralized and which they were last biased, in. a manner non-effective in the line relay 45, may traverse-the contacts 57 of the switching relay the first figure. 56, the line conductor L, the contacts 17 of ,In transmitting from the set C the key 4 the relay 16 at the first station, thence controls the pole-changer 32 whereby the through a polar line relay 5'which is assoline batteries 34 and 35 may be connected ciated with an artificial line AL to form a to act over the duplexed circuit and cause second differential or polar duplex wherein the line relay 45 to work the associated rethe currents from the distant station, as ceiving device--46. As well un derstood, the traced, may disturb the duplex balance and duplex equipments provide. that. service cause the armature oi this relay to be recipfrom the transmitting set C may be entirely rocated to correspond with the polarity of independent from, and carried on simultathe incoming currents. The line relay 5 neously with, service from the transmitting controls a local circuit which includes a set H. Therefore, it is necessary that the sounder 6, the primary winding 14 of the telegraphic traffic be distributed in such a transformer 13 and the contacts of the manner that the master set H may be conswitching relay 10 through which the cir-' tinuously busy'in orden' to render the secret cuit may be switched from one to the other service switching operations eflective. of the batteries 11 and 12. Assuming for In situations where 'theamount of traflic purpose of illustration that while the vawould Ifiake i t desirable, dh1(plex'eqiiipments O and rious equipments are at rest in the position typical of the equipments may be shown, at the master set H the transmitting substituted for the equipments E and F,

similar to that described in connection with key 44 is opened, the relay 62 thereupon rethereby providing fora capacity of four leases to connect the positlvely poled battery channels which may be operated simulta- 65 over the circuits already traced to the neously between the station A and the starelay 5 at the first station and biases the tion armature of that relay to its idle contact to The effectiveness of the secret service as thereby disconnect the local circuit already already pointed out in connection with the, traced through the sounder 6. Cessation of arrangement shown in Fig. 1 is also present current through the winding 14 of the trans with the arrangement shown in the second former 13 induces a momenta current in figure, and it maybe pointed out that in the secondary winding 15 where the polaraddition the increased amount of teleized switching relays 10, 16 and 19 will be graphic trafiic possible with the duplexed' operated in the same manner and for the arrangement serves to render the cryptosame control purposes as already described -graphlc effects even more intricate and infor the corresponding circuits in the first volved.

figure. At the station B, coincident with Referring'to Fig. 3 of the drawing this the release of the relay 62, the relay 63 also arrangement difiers from the arrangement restores to disconnect the local battery cirshown in Fig. 1 in that the transformer 53 cuit through. the; winding 54 of the transat the statlon B is controlled in a local cirformer 53; Cessation of current through cuit connected through the contacts of the the winding 54 induces "a momentary current line relay 45 of the set D. It willbe obviin the secondary 55 whereby the polarized ous that by this arrangement the same secret switching relays 50, 56 and 59 are operated service results as already described may be in the same gfnanner and to establishcircujt attained,- and that either the transmitting changes similar to those. already described key 4 of the set Cor the transmitting key 44 in'connection with the corresponding relays of the set D may serve as masters with reof the equipment shown in Fig. 1. Closure spect to controlling the operations of the. of the key 44 causes the operation of the secret service switching relays. The detailed descriptions already given in connection with Flgs. 1 and 2 are deemed to be suflicient to render further description of the third arrangement unnecessary.

Referring to the fact that manually operated telegraphic equipments have been illustrated in the drawing it will be understood that such equipments were chosen merely as a matter of convenience and that any suitable type of the many automatic transmitting and receiving systems may be substituted for the manual equipments without departing from the spirit of this invention.

\Vhat is claimed is:

1. In a system of secret telegraphy, a plurality of conductors extending from a first to a second station, means for providing a plurality of telegraphic channels between said stations, and means controlled through the transmission of impulses over accrtain one of said channels to divide the impulses therefrom between said plurality of conductors and likewise to divide the individual impulses of the other of said channels between said plurality of conductors.

2. In a system of secret telegraphy, means for providing a plurality of telegraphic channels between remote stations, electroresponsive means ateach station, and means controlled by the transmission of messages on one of said channels to vary the relation of said plurality of channels one with another.

3. In a system of secret telegraphy, a plurality of line conductors, means for controlling a plurality of channels in signaling over said line conductors, and means controlled by the transmission of signals over certain of said channels for reciprocally varying the relation of said channels with respect to said plurality of line conductors.

4. In a system of secret telegraphy, a plurality of dnplexed line conductors, means for providing a plurality of telegraphic channels over said line conductors, and means controlled by the operation of certain of said channels for reciprocally varying the relation of said channels with respect to said plurality of duplexed line conductors.

In a system of secret telegraphy, remote stations, a plurality of conductors joining said stations, pluralities of transmitting and receiving equipments to providea plurality of channels for communication between said stations, a plurality of relays for varying the relation of said telegraphic channels with respect to said plurality of line conductors, current transformer means controlled in the working of certain of said telegraphic channels for controlling the operation of said relays, and further means controlled by said transformer for varying the control efi'ect of said transformer.

6. In combination with a telegraph system a plurality of conductors extending between a first and a second station, a plurality of relays at each of said stations, a plurality of telegraphic channels completed through the contacts of said relays, and means responsive to the transmission of a message over one of said channels for operating said relays to thereby divide the individual impulses of a message between said plurality of conductors.

7. In a system of secret telcgraphy, a first station, a plurality of transmitting and receiving equipments at said station, several polar relays and a transformer at said station, a remote station having equipment typical of said first station, a plurality of line conductors joining said stations, and means reciprocally controlled by one of said telegraphic equipments at each station for controlling the operation of said polar relays, means controlled by certain of said relays for varying the connective relation of said telegraphic equipments with respect to said line conductors, and means controlled by other of said polar relays for varying the eflect of-the control as established by said transformers.

8. "In combination with a telegraph system, a plurality of conductors extending between a first and a second station, a plurality of relays at each of said stations normallyoperative by a current flow in one direction, and means responsive to the transmission of a message over one of said channels for reversing the direction of current flow through said relays to thereby divide the impulses of a message between said plurality of conductors.-

In witness whereof I hereunto subscribe my name this 19th day of June, A. D. 1918.

' AUGUSTUS J. EAVES. 

